Explosive land mine



Dec. 21, 1948. H, F, AGTS 2,456,657

EXPLOS IVE LAND MINE Filed Dec. '19 1944 Impu/Je 3mm Hale RVaH is a. amdx 8PM W junction with an impulse transmitter and re-. ceiver for arming the mine by remote control.v

Thus a friendly vehicle carrying an impulse radio transmitter, and pursued by a column of enemy vehicles, could arm the mines by radio are touching connected contact points, current flows in the coil 88, actuating the relay 90, and bringing contacts 92 and 94 together. The battery 86 is connected in a series circuit with the contacts 92 and 94, a solenoid coil 96 and a normally open pressure actuated switch 98 which is depressed when the pressure plate or spider of the mine is depressed, through any convenient type of mechanical linkage, causing current to flow in the coil 96, drawing into the coil a plunger I00 having an extension forming a pawl I02 which is adapted impulses as it passes across the mine field,- thus placing them in readiness for being exploded by the pursuing tanks in the manner already described for Figure 1. Each mine would be equipped with an impulse receiver and the arming andfiring mechanism as shown in Figure 2.

In .Figure. 2, an impulse transmitter 54 is mounted in a control vehicle. The radio transmitter 54 may have a radio frequency oscillator circuit feeding an antenna and keyed by a telephone dial mechanismof a type similar to those used on automatic dial telephones so that any desired number of impulses may be keyed automatically. Since the control vehicle will normallynbe ve'ry close to the mines being armed, the transmitter 54 may be of very low power'output.. The impulse radio receiver 56 may be of any usual form of detector-amplifier circuit, of the type commonly used for remotely controlled receivers such as those employed in some radio receivers, a thyratron output circuit being used to cause each impulse received to release sufficient output current to actuate the relay 58 causing the normally separated contacts 60 and 62 to be brought together. This causes current from the battery 64 to flo through the solenoid coil 66, drawing in the plunger 68 having a pawl I0 attached to it. The movement of the pawl I0 causes the ratchet wheel I2 to rotate about its center I4 and ad- Vance a distance equal to one notch of the ratchet I2. The contact arm 76 being fastened or keyed to the ratchet wheel I2, is also caused to advance tactpoint in the series of spaced contact points 28 arranged along the arc of a circle defined by the traverse of the outer end of the contact arm I6, as already explained for Figure 1. A series of spaced contact points 80 is arranged along the arc of a circle, and each contact point 80 is connected to the corresponding contact point I8 as shown in Figure '2.

A contact arm 82 pivoting on a center 84 is adapted to make contact with any selected contactpoint 80 by manual adjustment of contact arm 82. It is thus seen that if contact arm 82 is set on the second of the contact points 80 as shown in Figure 2, it will be necessary to move contact arm IS in a clockwise direction until it is touching the second of the contact points I8 before contact arms I6 andv 82 are electrically connected together. The two contact arms are con nected in a series circuit with a battery 86 and the, coil 88 of a relay 90 having a fixed contact 92 and a movable contact 94 mounted on an iron armature in the usual manner, whereby current in coil 88 causes contacts 92 and 94 to be brought together.

Thus, when contact arms "I6 and. 82

from one of the contact points I8 to the next con- 3 to engage the teeth on a rotatable ratchet wheel I04, mounted on a center pivot I06. A contact arm I08 rotatably mounted on the pivot I06 is keyed to the ratchet wheel I04 so they rotate together. Along the arc traversed by the outer end of the contact arm I08 is placed a series of spaced contact points I I0, so that the said contact arm may touch any of the said contact points.

A contact arm II2 rotatably mounted on a pivot I I4 traverses an are along which is aseries of spaced contact points I I6 and the contact arm I I2 may be manually rotated to touch any selected contact point 6. .The contact points H0 are each connected to corresponding contact points II6 as shown. The two sets of contact points III] and H6 and the contact arms I08 and H2 are connected in a series circuit, as shown, with a battery H8 and an electric detonator I20 adapted to explode the main charge of the mine.

The procedure for using the device shown in Figure 2, may now be summarized briefly as follows. The mines each containing the impulse receiver and the selective stepper mechanism described above, are to be placed under the terrain or road to be traversed by the retreating friendly vehicle carryingthe impulse transmitter 54. The first group of mines is set to be armed by one impulse, as shown in Figure 2, contact arm 82 being set to the position shown. Then a single impulse from the transmitter 54 as it passes over the first group of mines, causes the contact arm I6 to be moved over one notch to the second of the contact points I8, closing the series circuit, actuating relay and drawing contacts 92 and 94 together. The efiect is to place the mine in operative condition, that is, the mine is then in readiness to explode when the third of a column of hostile vehicles has passed over its pressure plate, the three vehicles having thus depressed the switch 98 a total of three times. If contact arm I I2 were on the fifth of the contact points I I6 instead of the fourth as shown in the drawing, then four hostile vehicles would actuate the switch 98 before the mine would explode;

Different groups of mines could be set to be armed by different numbers of impulses bysuitably adjusting contact arm 82 to the desired'contact point 80. 1

If mines are too closely space'd'there is a possibility of an impulse intended for one mine causing the ratchets I2 of other mines to advance.

To offset this, it may be desirable to equip the ratchet wheels I2 with a simple mechanical spring arrangement for returning them to their zero position when any series of impulses does not in phonograph reproducers which are remotely controlled by radio may be employed:

While the foregoing specification sets forth the invention in specific terms, it is to be understood 1 that numerous changes in the shape, size, ar rangement and materials may be resorted to without departing from the spirit and scope of the invention as claimed herein.

' Iclaim:

In an explosive mine having a main charge, an electric circuit comprising an electric detonator for exploding said main charge, a battery connected to the detonator for exploding the same, and switch means in said circuit for closing the same thereby actuating said detonator, said switch means comprising a pair of terminals, the first terminal connected to a pivot, a manually operable contact arm rotatably mounted on said pivot and electrically connected thereto, a plurality of spaced contact points disposed along the arc of a circle traversed by the outer end of said contact arm, said contact arm being rotatably adapted to touch any selected contact point, a second pivot electrically connected to the second terminal of said switch means, a second contact arm rotatably mounted on said second pivot and electrically connected thereto, a second plurality of spaced contact points disposed along the arc of the circle traversed by the outer extremity of said second contact arm and equal in number to the first plurality of contact points, corresponding contact points in said first and second pluralities of points being connected together in pairs, elec tromagnetic means engaging said second pivot for stepwise unidirectional rotation, a source of electric potential for energizing said electromagnetic means for a single impulse, and pressure operated switch means for closing the circuit to said electromagnetic means.

HALE F. VAGTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 850,972 Schneider Apr. 23, 1907 1,333,900 Clark Mar. 16, 1920 20 1,623,475 Hammond, Jr Apr. 5, 1927 FOREIGN PATENTS Number Country Date 541,624 Great Britain Dec. 4, 1941 594,479 France June 22, 1925 826,676 France Jan. 8, 1938 

